Wool Cigarette Filters Part II: Modifications to Promote the Selective Removal of Biologically Active Vapour Phase Components

Modified-wool cigarette filters have been evaluated for their efficiency in selectively retaining specific biologically active volatile and semivolatile smoke components. Filters containing chemically modified wools or wool treated with low-molecular-weight additives were ineffective. Polymeric additives reduced the cytotoxic level of cigarette smoke by varying degrees. Polyethylenimines were particularly effective additives and selectively removed portions of formaldehyde, acetaldehyde, acrolein, hydrogen cyanide, phenols and other weakly acidic compounds. Increasing the moisture content of the treated filters markedly improved their performance. The effectiveness of polyethyleniminetreated filters in removing volatile aldehydes was strongly dependent on the pH of the filter, most efficient removaI occurring at pH 6.0-6.2.